“Kittinger followed this flight with two more. Excelsior II launched on December 11, 1959 and rose to a height of 74,700 before Kittinger left the gondola. His final flight in this series, Excelsior III, took place on August 16, 1960. Kittinger piloted his craft to an altitude of 102,800 feet before exiting the open gondola. On the descent Kittinger became the first man to exceed the Speed of Sound without an aircraft or space vehicle. It is still the highest parachute jump ever. The freefall lasted four minutes and thirty-six seconds, a record.” cite
How did he manage this without being torn apart like some mid century aircraft did? One of the problems that certain aircraft had in power dives was not being streamlined enough to handle the transition from sub to supersonic.
So the human body is streamlined enough? (I guess so, Joe survived.) Were his drag chutes automatically deployed? Did he have to move his his arms in order to pull some rip cord?
I’m not doubting this happened. I can find all sorts of cites online about, as well as a couple of books I have mentioning it. And I just saw some snippets of the film he made of it on some cable science show. But it’s the details that have me flummuxed. Just what were the mechanics of his being able to do this?
NOVA Online has the episode Skydive From the Stratosphere available for download. Anyone see it? Does that episode answer my specific questions in the OP? Does it focus on the dive, or is it more of a bio of Kittenger? (I guess I missed when this first aired.)
The speed of sound varies with altitude, or more preciselly with air density. At 19 miles Mach 1 is about 675 mph (760 at sea level); so the guy didn´t have to move quite as quickly. That and ,to a greater extent, the very rarified air at that height leaded to much lower aerodynamic forces.
Nevertheless I bet that must have been a hell of a ride.
It varies with density only slightly. (and would not at all if air were an ideal gas) It varies with temperature a lot. At a given temperature, SOS will be nearly constant at all altitudes and pressures (while density will be directly proportional to pressure) . Air data systems correct mach readings for temperature but not pressure. Because it is more than a bit tricky to measure ambient temperature around an aircraft traveling at high speed, temperature measurement error introduces far more error than ignoring the minimal effect of pressure.
SOS thus decreases steadilly to around 35,000’ MSL, stays pretty constant up to ~75,000, then increases rapidly above that.
At constant temperature, the compliance (spring constant) of an ideal gas changes with density in such a way as to maintain constant SOS.
I should point out that, as I was checking out just about every one of the seven dozen some odd sites that my searches turned up last night, quite a few of the sites mention that his breaking the sound ‘barrier’ is disputed. Some say he reached only Mach 0.9 (at about 615 knots, iirc, whatever altitude range that would be…).
Some of the sites also talk about his stabalizing chute system, which apparantly deployed somewhere in the first 20K ft of freefall, so he wouldn’t be torn to shreds by any areodynamic forces.
Still a lot of left out info, imho. I would love to find something detailed about those three stratojumps.
What is supposed to be the source of these incredible forces that will rip a human body apart?
The main forces in play would seem to be gravity (a few hundred pounds downward) and aerodynamic drag (at terminal velocity, equal and opposite to gravity).
I’ve read the OP and I still think Xema’s question is valid. No matter how strong the aerodynamic drag is, the only force pushing a skydiver against this aerodynamic drag is gravity.
Thanks for the reminder - I did read the OP before posting.
It does in fact take more force to drive an aircraft (or other object) at supersonic as compared to subsonic speeds. At the altitudes that aicraft flew when supersonic flight was first being attempted, the necessary increase in thrust was a real problem. Part of the solution was to change the shape of the fuselage (the “area rule”).
But if Kittinger exceeded the speed of sound, this happened at a much higher altitude, where the air is much less dense and so the required force is much lower. My point is that the available force was no more than his weight, which argues that there was not sufficient force to rip a body apart.
Skydive From the Stratosphere would not download nor run on XP.
A high altitude sky dive is affected by 1. Gravity and 2. Aerodynamic drag.
The aerodynamics of the falling object, Joe Kittenger, as well as drag chutes etc. determine the terminal velocity. Without instrumented data collection system(s) to verify the maximum velocity there will continue to be skeptics of the claimed achievement.
Sweet. Apologies for over-reacting to what looked a snarky reply earlier. Having seen people flail about and lose control in regular skydiving, I was wondering what such high speeds reached in stratojumping might do. I guess the density factor is the main difference here. (In the site in my OP, Kittenger makes mention of no billowing or flapping of his suit as left the gondola.)
So, how far down would a person need to stay in free fall before drag becomes a major issue?
:smack: :rolleyes: